1. Field of the Invention
The present invention relates generally to coupling systems for attaching foundation piers to movable dwellings, such as mobile homes, commercial coaches and temporary and emergency offices, and more particularly, to an improved coupling system for semi-permanently attaching a foundation pier to a movable dwelling and that allows the foundation pier to be secured during transit of the movable dwelling without reducing ground clearance of the dwelling during transit.
2. Description of Related Art
Within the context of movable structures, foundation systems that can be relatively easily disassembled are generally preferred. Foundation systems that incorporate independently positionable piers are therefore especially appropriate for movable dwellings, such as mobile homes, commercial coaches and certain types of temporary or emergency offices.
The structural designs of movable dwellings are typically developed to enhance the facile transportability characteristics of the dwelling on roadways. This design consideration usually results in dwellings that have a larger length dimension than width dimension, in order to maximize floor space but be most suitable transporting the dwelling to a desired installation site, via a truck for example.
Most mobile dwellings are provided with a plurality of spatially positioned, elongated support girders or beams that extend parallel to the longer axis of the structure. The support beams often have an "I" cross sectional configuration. A plurality of spatially positioned floor joists, that may have either a "J" or "C" cross sectional configuration, are supported by the beams and extend across the width of the unit. Some movable dwellings may incorporate a perimeter chassis with a beam having a "C" configuration.
The incorporation of a plurality of piers placed under an intersecting pattern of support beams and floor joists is a therefore a common and preferable type of foundation system when installing the movable dwelling at an installation site. The piers transfer and support the weight of the dwelling from a beam to a ground surface. The piers are frequently positioned at key structural locations within the foundation system and beneath a beam, such as at an intersection of the beam and a joist. Foundation systems employing C-beams may have piers spatially positioned along the beam at predetermined intervals to support the unit. The placement pattern of the piers and the distances between piers may also be governed by such factors as the dimensions of the unit and applicable building codes at the installation site of the unit.
Foundation piers in the prior art often comprise a base plate for supporting the pier on the ground of the installation site and a pair of opposing supports affixed to the base. Adjustable extensions are included for adjusting the height of the pier. The piers may include suitable means affixed to the extensions for coupling the extensions to a beam of the unit. The coupling means often comprises a platform that has upwardly extending threaded shafts. A plate is held in a desired horizontal position by the threaded shafts using well known methods. The plate is adjusted upwardly until it abuts the beam. A pair of brackets, coupled to the shafts, are placed over the bottom portion of the desired beam and tightened onto the beam, to secure the pier to the beam.
Another prior art foundation pier is disclosed in U.S. Pat. No. 5,595,366, to Cusimano et al. The pier disclosed therein is directed to supporting a movable dwelling, such as a mobile home or commercial coach. The disclosed pier includes a base plate having a threaded shaft, with a plurality of webs spatially positioned about the shaft. A support member has a first end threadably coupled to the shaft for adjusting the height of the pier. Couple members are detachably coupled to a second end of the support member. The couple members attach the pier to a support beam of the movable dwelling, to prevent movement between the pier and the dwelling. A clamp member, affixed to the plurality of webs, couples to the support member for preventing movement of the support member relative to the shaft and the clamp member. Environmental forces applied to the support member are transmitted from the clamp member and distributed through the plurality of webs to prevent the pier from collapsing.
However, it is disadvantageous that the pier is not at least semi-permanently attached to the unit. Since prior art piers are not semi-permanently attached to the unit, they are installed once the unit is at the desired installation site, instead of prior to transporting the unit to the site. Often, the piers are improperly installed, potentially causing the pier to fail, and thus damaging either the unit, the pier, or both.
U.S. patent application Ser. No. 08/650,183, filed May 20, 1996 by the Applicant, now U.S. Pat. No. 5,711,504, and incorporated herein in its entirety by reference, discloses a pier that provides hingeable coupling means for coupling the pier to the foundation of a movable dwelling. The disclosed pier can be alternatively pivoted from a transportation position and into a load bearing position, or installation position, and back to the transportation position. A retaining member is provided for retaining the pier in the transportation position to prevent the pier from accidentally contacting a ground surface during transportation of the movable dwelling. In the transportation position, the pier is located below the lower edge of a beam and thus reduces the ground clearance during transit of the movable dwelling to the installation site.
Therefore, there still exists a need for a coupling system that semi-permanently attaches a foundation pier to a moveable dwelling, that easily and safely stows and secures the foundation pier during transit of the moveable dwelling and does not reduce the ground clearance of the movable dwelling during transit.